本文整理了Java中java.util.Collections.emptyList()方法的一些代码示例，展示了Collections.emptyList()的具体用法。这些代码示例主要来源于Github/Stackoverflow/Maven等平台，是从一些精选项目中提取出来的代码，具有较强的参考意义，能在一定程度帮忙到你。Collections.emptyList()方法的具体详情如下：
包路径：java.util.Collections
类名称：Collections
方法名：emptyList

Collections.emptyList介绍

[英]Returns a type-safe empty, immutable List.
[中]返回类型安全的空不可变列表。

代码示例

代码示例来源：origin: square/retrofit

@Override List<? extends Converter.Factory> defaultConverterFactories() {
 return Build.VERSION.SDK_INT >= 24
   ? singletonList(OptionalConverterFactory.INSTANCE)
   : Collections.<Converter.Factory>emptyList();
}

代码示例来源：origin: spring-projects/spring-framework

private Object formatLocations() {
    if (!this.locationValues.isEmpty()) {
      return this.locationValues.stream().collect(Collectors.joining("\", \"", "[\"", "\"]"));
    }
    else if (!this.locations.isEmpty()) {
      return "[" + this.locations + "]";
    }
    return Collections.emptyList();
  }
}

代码示例来源：origin: bumptech/glide

@NonNull
@Override
public List<MediaStoreData> getPreloadItems(int position) {
 return data.isEmpty()
     ? Collections.<MediaStoreData>emptyList()
     : Collections.singletonList(data.get(position));
}

代码示例来源：origin: redisson/redisson

/**
   * {@inheritDoc}
   */
  public Iterable<? extends List<Class<?>>> batch(List<Class<?>> types) {
    if (types.isEmpty()) {
      return Collections.emptyList();
    } else {
      List<List<Class<?>>> batches = new ArrayList<List<Class<?>>>();
      int size = types.size() / parts, reminder = types.size() % parts;
      for (int index = reminder; index < types.size(); index += size) {
        batches.add(new ArrayList<Class<?>>(types.subList(index, index + size)));
      }
      if (batches.isEmpty()) {
        return Collections.singletonList(types);
      } else {
        batches.get(0).addAll(0, types.subList(0, reminder));
        return batches;
      }
    }
  }
}

代码示例来源：origin: dropwizard/dropwizard

private List<Pattern> getNonProxyHostPatterns(@Nullable List<String> nonProxyHosts) {
  if (nonProxyHosts == null) {
    return Collections.emptyList();
  }
  final List<Pattern> patterns = new ArrayList<>(nonProxyHosts.size());
  for (String nonProxyHost : nonProxyHosts) {
    // Replaces a wildcard to a regular expression
    patterns.add(Pattern.compile(WILDCARD.matcher(nonProxyHost).replaceAll(REGEX_WILDCARD)));
  }
  return Collections.unmodifiableList(patterns);
}

代码示例来源：origin: spring-projects/spring-framework

@Override
protected List<String> getNonOptionArgs() {
  List<?> argValues = this.source.nonOptionArguments();
  List<String> stringArgValues = new ArrayList<>();
  for (Object argValue : argValues) {
    stringArgValues.add(argValue.toString());
  }
  return (stringArgValues.isEmpty() ? Collections.emptyList() :
      Collections.unmodifiableList(stringArgValues));
}

代码示例来源：origin: spring-projects/spring-framework

/**
 * Assert that the listener identified by the specified id has received the
 * specified events, in that specific order.
 */
public void assertEvent(String listenerId, Object... events) {
  List<Object> actual = this.content.getOrDefault(listenerId, Collections.emptyList());
  assertEquals("Wrong number of events", events.length, actual.size());
  for (int i = 0; i < events.length; i++) {
    assertEquals("Wrong event at index " + i, events[i], actual.get(i));
  }
}

代码示例来源：origin: spring-projects/spring-framework

@SuppressWarnings("unchecked")
static <T> List<T> getAdviceByType(@Nullable List<Object> requestResponseBodyAdvice, Class<T> adviceType) {
  if (requestResponseBodyAdvice != null) {
    List<T> result = new ArrayList<>();
    for (Object advice : requestResponseBodyAdvice) {
      Class<?> beanType = (advice instanceof ControllerAdviceBean ?
          ((ControllerAdviceBean) advice).getBeanType() : advice.getClass());
      if (beanType != null && adviceType.isAssignableFrom(beanType)) {
        result.add((T) advice);
      }
    }
    return result;
  }
  return Collections.emptyList();
}

代码示例来源：origin: ReactiveX/RxJava

@Test
public void mergeBiFunction() throws Exception {
  MergerBiFunction<Integer> f = new MergerBiFunction<Integer>(Functions.<Integer>naturalComparator());
  assertEquals(0, f.apply(Collections.<Integer>emptyList(), Collections.<Integer>emptyList()).size());
  assertEquals(Arrays.asList(1, 2), f.apply(Collections.<Integer>emptyList(), Arrays.asList(1, 2)));
  for (int i = 0; i < 4; i++) {
    int k = 0;
    List<Integer> list1 = new ArrayList<Integer>();
    for (int j = 0; j < i; j++) {
      list1.add(k++);
    }
    List<Integer> list2 = new ArrayList<Integer>();
    for (int j = i; j < 4; j++) {
      list2.add(k++);
    }
    assertEquals(Arrays.asList(0, 1, 2, 3), f.apply(list1, list2));
  }
}

代码示例来源：origin: ReactiveX/RxJava

@Override
  public Iterable<Integer> apply(Integer v) throws Exception {
    if ((v & 1) == 0) {
      return Collections.emptyList();
    }
    return Arrays.asList(1, 2);
  }
})

代码示例来源：origin: spring-projects/spring-framework

/**
 * Parse the given list of (potentially) comma-separated strings into a
 * list of {@code MediaType} objects.
 * <p>This method can be used to parse an Accept or Content-Type header.
 * @param mediaTypes the string to parse
 * @return the list of media types
 * @throws InvalidMediaTypeException if the media type value cannot be parsed
 * @since 4.3.2
 */
public static List<MediaType> parseMediaTypes(@Nullable List<String> mediaTypes) {
  if (CollectionUtils.isEmpty(mediaTypes)) {
    return Collections.emptyList();
  }
  else if (mediaTypes.size() == 1) {
    return parseMediaTypes(mediaTypes.get(0));
  }
  else {
    List<MediaType> result = new ArrayList<>(8);
    for (String mediaType : mediaTypes) {
      result.addAll(parseMediaTypes(mediaType));
    }
    return result;
  }
}

代码示例来源：origin: skylot/jadx

public static List<BlockNode> bitSetToBlocks(MethodNode mth, BitSet bs) {
  int size = bs.cardinality();
  if (size == 0) {
    return Collections.emptyList();
  }
  List<BlockNode> blocks = new ArrayList<>(size);
  for (int i = bs.nextSetBit(0); i >= 0; i = bs.nextSetBit(i + 1)) {
    BlockNode block = mth.getBasicBlocks().get(i);
    blocks.add(block);
  }
  return blocks;
}

代码示例来源：origin: google/guava

public void testPartition_empty() {
 List<Integer> source = Collections.emptyList();
 List<List<Integer>> partitions = Lists.partition(source, 1);
 assertTrue(partitions.isEmpty());
 assertEquals(0, partitions.size());
}

代码示例来源：origin: spring-projects/spring-framework

@Test
public void path() throws Exception {
  // basic
  testPath("/a/b/c", "/a/b/c", Arrays.asList("/", "a", "/", "b", "/", "c"));
  // root path
  testPath("/", "/", Collections.singletonList("/"));
  // empty path
  testPath("", "", Collections.emptyList());
  testPath("%20%20", "%20%20", Collections.singletonList("%20%20"));
  // trailing slash
  testPath("/a/b/", "/a/b/", Arrays.asList("/", "a", "/", "b", "/"));
  testPath("/a/b//", "/a/b//", Arrays.asList("/", "a", "/", "b", "/", "/"));
  // extra slashes and spaces
  testPath("/%20", "/%20", Arrays.asList("/", "%20"));
  testPath("//%20/%20", "//%20/%20", Arrays.asList("/", "/", "%20", "/", "%20"));
}

代码示例来源：origin: spring-projects/spring-framework

/**
 * Returns the value of the {@code Sec-WebSocket-Key} header.
 * @return the value of the header
 */
public List<String> getSecWebSocketProtocol() {
  List<String> values = get(SEC_WEBSOCKET_PROTOCOL);
  if (CollectionUtils.isEmpty(values)) {
    return Collections.emptyList();
  }
  else if (values.size() == 1) {
    return getValuesAsList(SEC_WEBSOCKET_PROTOCOL);
  }
  else {
    return values;
  }
}

代码示例来源：origin: google/guava

@SuppressWarnings("unchecked") // dang varargs
 @Override
 <T> Scenario<?> mutate(Scenario<T> scenario) {
  List<Iterable<T>> words = Lists.newArrayList();
  words.add(Collections.<T>emptyList());
  for (T t : scenario.strictlyOrderedList) {
   words.add(Arrays.asList(t));
   for (T s : scenario.strictlyOrderedList) {
    words.add(Arrays.asList(t, s));
   }
  }
  return new Scenario<Iterable<T>>(
    scenario.ordering.lexicographical(), words, new Iterable[0]);
 }
},

代码示例来源：origin: spring-projects/spring-framework

/**
 * Returns the value of the {@code Sec-WebSocket-Extensions} header.
 * @return the value of the header
 */
public List<WebSocketExtension> getSecWebSocketExtensions() {
  List<String> values = get(SEC_WEBSOCKET_EXTENSIONS);
  if (CollectionUtils.isEmpty(values)) {
    return Collections.emptyList();
  }
  else {
    List<WebSocketExtension> result = new ArrayList<>(values.size());
    for (String value : values) {
      result.addAll(WebSocketExtension.parseExtensions(value));
    }
    return result;
  }
}

代码示例来源：origin: ReactiveX/RxJava

@Test
public void request() {
  TestResourceSubscriber<Integer> tc = new TestResourceSubscriber<Integer>() {
    @Override
    protected void onStart() {
      start++;
    }
  };
  Flowable.just(1).subscribe(tc);
  assertEquals(1, tc.start);
  assertEquals(Collections.emptyList(), tc.values);
  assertTrue(tc.errors.isEmpty());
  assertEquals(0, tc.complete);
  tc.requestMore(1);
  assertEquals(1, tc.start);
  assertEquals(1, tc.values.get(0).intValue());
  assertTrue(tc.errors.isEmpty());
  assertEquals(1, tc.complete);
}

代码示例来源：origin: skylot/jadx

public List<LoopInfo> getAllLoopsForBlock(BlockNode block) {
  if (loops.isEmpty()) {
    return Collections.emptyList();
  }
  List<LoopInfo> list = new ArrayList<>(loops.size());
  for (LoopInfo loop : loops) {
    if (loop.getLoopBlocks().contains(block)) {
      list.add(loop);
    }
  }
  return list;
}

代码示例来源：origin: jenkinsci/jenkins

private List<AbstractProject> get(Map<AbstractProject, List<DependencyGroup>> map, AbstractProject src, boolean up) {
  List<DependencyGroup> v = map.get(src);
  if(v==null) return Collections.emptyList();
  List<AbstractProject> result = new ArrayList<AbstractProject>(v.size());
  for (DependencyGroup d : v) result.add(up ? d.getUpstreamProject() : d.getDownstreamProject());
  return result;
}